merc 350 engine problems need input

[cobia-boat]

I was on the lake today, and it was running great. Stopped for some grub, then an hour later left and no waked it for about 5 min. Hammered down and bang bang bang. Pulled off cyl. 3 wire from dist. and it goes away. Sounds like something is banging by the intake. I had 20 miles to get home so i no waked it all the way home at 6 mph. to get it home running rough on 7 cyls. engine year is mid 80's on a 23 foot chris craft pre alpha outdrive

 

[firehog6305]

Re: merc 350 engine problems need input

sounds like a valve to me, or a pushrod problem, but i'm sure one of the master wrenchers on her will help

 

[Bondo]

Re: merc 350 engine problems need input

Ayuh,........

You might try a Compression Test,.......
But,......
It Sounds like it's time to Pull the Head,+ Look........

 

[Bt Doctur]

Re: merc 350 engine problems need input

may just be a broken rocker arm too

 

[cobia-boat]

Re: merc 350 engine problems need input

pulled the valve cover and on cyl. three one rocker arm broken off, right at the stud, and i can't see the valve??? (where could it go?) The other valve is loose and looks like the rod is maybe bent a little. I pulled the plug and it just looked oily.

 

[John_S]

Re: merc 350 engine problems need input

Proceed to pulling the head. At this point, you will be extremely lucky if there is no damage to piston or cyl wall, that will require engine rebuild.

 

[Don S]

Re: merc 350 engine problems need input

and i can't see the valve??? (where could it go?)

Probably in the cylinder and THRU the top of the piston.